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991.
992.
该文阐述了预制箱梁混凝土夏季施工的具体质量控制,并着重介绍了施工过程中的工序工艺控制要素、事故预防及处理。从而较好地控制质量,预防、减少或杜绝质量事故的发生。 相似文献
993.
该文针对宁波甬江特大斜拉桥主塔锚固区环向预应力束张拉时实际生产量与理论生产量之间的误差大于6%这一现象,系统地分析了影响环向预应力束伸长量的各种因素,指出了环向预应力束伸长量的构成特点。对主塔施工中实测伸长量比理论伸长量偏大这一现象给出了合理的解释。 相似文献
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995.
根据木槽岩隧道穿越区地质条件和实际施工情况,施工中采取了超前支护、分步开挖、稳步推进的方法,并增加了超前小导管及锁脚小导管、锁脚锚杆等支护方式,加强测量观测工作,避免不良地质给施工造成的损失。 相似文献
996.
FU Yu-wei YIN Hang YANG Gui-bin 《船舶与海洋工程学报》2005,4(3):64-70
Data envelopment analysis (DEA) model is widely used to evaluate the relative efficiency of producers. It is a kind of objective decision method with multiple indexes. However, the two basic models frequently used at present,the C^2R model and the C^2GS^2 model have limitations when used alone ,resulting in evaluations that are often unsatisfactory. In order to solve this problem, a mixed DEA model is built and is used to evaluate the validity of the business efficiency of listed companies. An explanation of how to use this mixed DEA model is offered and its feasibility is verified. 相似文献
997.
ZHAO Xi-ren PENG Xiu-yan and YIN Zhong-feng School of Automation Harbin Engineering University Harbin China 《船舶与海洋工程学报》2005,4(4):18-22
The robustness of LQG designing for latitudinal movement of ship is mainly discussed, when its hydrodynamic parameters fluctuate around criterion value at random on the proportional distributing. When a given ship state at the speed of 18 kn and the course of 45°under Rank 5 state of sea,and the hydrodynamic parameters of the ship fluctuate at random on the proportional distributing with a range of±10%,±20%,±30%,the robustness of multivariate LQG designing for ship is analyzed with applying the probability modeling of relative controlling effect. The result of simulating shows that when the hydrodynamic parameters of ship fluctuates the relative controlling effect of the LQG designing submit to normal distribution and the mean value of relative controlling effect has no remarkable changes comparing to that without perturbation of hydrodynamic parameter. 相似文献
998.
应用非线性最优控制方法,研究了高速公路网的匝道控制和路径诱导的集成问题,构造了集成控制的最优控制模型.在模型中,以路网总耗时最小为优化目标,以METANET模型为网络交通流模型,考虑了控制变量的更新周期约束,采用粒子群优化技术求解优化模型.仿真结果表明:无控制时,路网总耗时为3 376 veh·h;仅实施匝道控制时,路网总耗时为3 005 veh·h;仅实施路径诱导时,路网总耗时为2 768 veh·h;集成控制时,路网总耗时为2 464 veh·h.可见,集成控制效果最优. 相似文献
999.
Analyzing the interactions between spot and forward freight agreement (FFA) prices in the dry bulk shipping is important as they play a significant role for shipping companies to secure their profits and avoid potential risks in the volatile market. By applying the vector autoregression (VAR) and the vector error correction model (VECM), this paper identifies the long-run and mutual causal relationship between the spot and FFA prices on the BPI T/C and BCI C7 routes. Along with these cointegrating rates, exogenous factors such as the market demand and supply and some economic indices are also recognized as contributing variables for the dynamic movement of the spot and FFA prices. Importantly, the mean-reverting process is justified on both routes with different mechanisms. When the spot and FFA prices deviate from their equilibrium level in the short run, they will be adjusted to their long-run equilibrium more directly and clearly on the BPI T/C route than those on the BCI C7 route. It also indicates that this adjusting power has direction and size asymmetries on both routes. In addition, the impulse analysis indicates that the spot rate is more volatile than its corresponding FFA prices confronting innovations. The results of this study provide a reference to the participants in the dry bulk shipping market on the causes of fluctuation in spot and FFA prices and their interactions, which can be used to promote the risk management in the market. 相似文献
1000.
网络流量随机条件下的随机交通网络平衡分析 总被引:2,自引:0,他引:2
考虑到现实条件下交通网络的不确定性状态,提出了从确定型网络到不确定型网络状态下,出行者路径选择行为的改变,即由出行时间最短的路径选择行为转变为在追求一定行程时间可靠性的基础上选择出行时间最短的路径选择行为.考虑到网络上交通需求量的不确定性提出了最优可靠行程时间的概念.在此基础上将出行者追求最优可靠行程时间的路径选择行为纳入到随机交通网络平衡分配模型中,证明了模型的等价性和唯一性.最后在一个小型测试网络上对模型分配结果进行了测试,测试结果符合实际情况,表明模型能够较好地反映出行者的路径选择行为. 相似文献